Variable-speed opening and closing device



y 1962 H. KIELHORN 3,043,584

VARIABLE-SPEED OPENING AND CLOSING DEVICE Filed Nov. 4, 1959 Heinz Kielhorn INVENTOR.

24-, i BY 27 26a 26b 26c 23 26b z'su' FIG] W Y AGENT.

United States Patent 3,043,584 VARIABLE-SPEED OPENING AND CLOSING DEVICE Heinz Kielhorn, Strasse des Komsomol 373, Leipzig W. 43, Germany Filed Nov. 4, 1959, Ser. No. 850,812 3 Claims. (Cl. 268-53) My present invention relates to a variable-speed opening and closing device and, more particularly, to a device for opening and closing slidable shutter members such as furnace and elevator doors, gates, theater curtains, screens and the like.

Such sliding closure members require controlled opening and closing speeds, by reason of their large masses. Should a constant-speed motor, for example, be used with a conventional rack-and-pinion mechanism to drive massive doors, the initial torque of the motor would have. to be sufliciently large to overcome the rest inertia of the door, while the same torque,'applied to the door in motion, would tend to accelerate it to excessive speeds. Similarly, toward the end of the opening or closing stroke, the door must be slowed to a stop gradually, to prevent damage to the mechanism. For this purpose it has previously been the practice to employ direct-current motors and, consequently, expensive rectifiers as well as automatic regulating devices adapted to vary the electrical input to the motor to produce the appropriate door speeds. Other, single-speed systems in use heretofore, such as those operating on three-phase current, had to be equipped with complex and potentially troublesome speed-control elements such as brakes, worm-gear transmissions, slipping clutches, cam-wheel drives and the like; all of these devices are expensive to manufacture and subject to considerable wear, the same drawback being encountered with leadserew-type driving mechanisms. Hydraulic and pneumatic units require elaborate pumping or compressor apparatus, whereas ordinary friction-drum drives are applicable only to oversized doors, gates or the like which must be massive enough to exert the necessary contact pressure by their own weight.

It is, therefore, an object of the present invention to provide a reliable and inexpensive variable-speed device for opening and closing sliding doors and the like.

Another object of the invention is the provision, in such device, of a single driving element of simple construction, adapted to be readily replaced in case of wear, in combination with a follower element which can be easily exchanged to vary the speed cycle of the controlled member.

A further object of this invention is to provide means to enable changes in contact pressure between driving and driven element as well as compensation of normal wear.

In accordance with a feature of my invention I provide a motor-driven, rotary drive element of varying diameter, such as a cone or a stepped cylinder, adapted to bear upon and frictionally to engage an elongated follower element or rail carried by a displaceable member (eg a sliding elevator door) in order to impart varying rates of acceleration and displacement to that member according to the difierent distances of the contact surface from the axis of the drive element. Thus, given a generally conical (continuous or stepped) driving element rotating at a constant speed, a point on the periphery of the cone near the apex will travel at a measurably slower speed than a peripheral point near the base of the cone. A rail contacting the cone first at one and then at the other point will therefore be propelled successively at a lower and at a higher speed. Naturally, a door so constructed can co-operate with, or be supplemented by, a further door of conventional construction serving, for example, to close an elevator shaft.

Advantageously, the generally conical driving element is mounted on a shaft which, e.g. by being supported on a swingable gear housing, is mounted for limited adjustment of its spacing from the follower element to establish a desired contact pressure and to maintain such pressure after the parts have become slightly worn.

The above and other objects, features and advantages of my present invention will become more readily apparent from the following description, reference being made to the accompanying drawing in which:

FIG. 1 is a front-elevational view of an elevator-door opening device according to the invention;

FIG. 2 is a similar view showing the elevator door in a partially opened position;

FIG. 3 is a side-elevational view of the device shown in FIGS. 1 and 2;

FIG. 4 is a top-plan view of the device;

FIG. 5 is a view, similar to FIG. 1, of a second embodiment of the invention;

FIG. 6 is a side-elevational view of the second embodiment; and

FIG. 7 is a top-plan view of the embodiment shown in FIGS. 5 and 6.

In FIGS. 1 to 4 I show an elevator frame .1 having an entrance way 2 adapted to be closed by a sliding door 3 whose rollers 5 are carried by a runner 4 extending the width of the elevator to which it is secured. The door 3 is provided with a bracket-shaped friction rail 6 having two spaced-apart, co-linear end sections 6a, 6a, whose upper surfaces are parallel to the top edge of door 3, interconnected by a longer central section 60 of a height less than that of sections 6a, 6a and by a pair of intermediate, inclined ramp sections 6b, 6b. The two end sections 6a, 6a are substantially flush with the front surface of the door 3, while the central section 6c is substantially aligned with the rear surface of the door. The

elevator also carries a squirrel-cage motor 11 which rotates a conical drive roller 7 bearing upon rail 6. Roller 7 is driven by the motor via a speed reducer, lodged in a housing 10, which comprises a pinion 8 connected to a motor shaft 8 and a driven gear 9 on whose shaft 9' the roller 7 is carried. Housing '10, swingable about shaft 8, has a. flange 10 traversed by a screw 11 for fixing it in different angular positions to the housing of motor 11, thereby varying the contact pressure between roller 7 and rail 6. Motor 11 is controlled by a conventional elevator circuit schematically shown as a network 15 provided with a pushbutton 14 and with a time-delay relay 12 which is controlled by a limit switch 13 to reverse the motor, in a manner known per se, if the switch 13 is not operated a predetermined interval after actuation of button 14 to close the door, thus indicating the presence of an obstacle in the path of the door. Other safety circuits known in the art may, of course, also be used to arrest or to reverse the motor whenever the door 3 is blocked in some intermediate position against the driving friction between roller 7 and rail 6.

To open the door 3, an actuating device such as the pushbutton 14 is operated to energize the motor 11. By the consequent rotation of drive roller 7 in a clockwise direction, as viewed in FIG. 1, the rail 6 and the door 3 secured thereto are displaced in the direction of the arrow A to the open position thereof (shown in dot-dash lines). Upon the starting of the motor 11, rail portion 6a contacts the conical surface of the roller 7 at a point near the apex of that roller. Owing to the small diameter of the roller at this point, a relatively large force, determined by the torque of the roller 7 at the pointof contact, is transmitted to the door 3, thereby overcoming the inertia of the heavy stationary door body without undue strain on the motor. As the door is displaced in the direction of the arrow A, the rail 6 contacts the roller 7 at peripheral points approaching the base of the cone and, therefore, is displaced at increased speed but with reduced torque. Subsequently, the door reaches its maximum desired velocity with which it continues to travel as long as the roller 7 is in contact with the rail 6 along its low-elevationsection 60. When the door 3 is opened sufiiciently for the roller 7 to contact the ramp section 6b, its motion is slowed until, as the end section 6a is engaged at a point on the conical roller surface once again near the apex of the cone, its speed sufliciently low to permit the motor to be cut ofi and brought to a stop, by the operation of a suitable switch not shown without undue strain upon any part of the system. The closure movement is, of course, substantially identical with the opening movement, owing to the symmetry of the rail 6. Upon contact of end portion 6a with the switch 12, the motor 11 is cut off and the elevator is ready for the next cycle.

As best seen in FIG. 3, the rail 6 in projection upon a transverse plane has a profile which is complementary to that of cone 7. This figure also shows the adjustable mounting of motor base 16 on a threaded stem 17 about which it may thus be swung for proper alignment of roller 7 with rail 6.

In FIGS. 5, 6 and 7 I show a second embodiment of the invention wherein a stepped cylinder27 also of broad ly conical outline, comprising a small-diameter disk 27a, an intermediate disk 27b anda large-diameter disk 27c, has replaced the conical roller 7 of FIGS. 1-4; a stepped rail 26, comprising a pair of high-elevation end sections 26a, 2621", a pair of intermediate sections 26b, 26b and a low-elevation central section 260, has replaced the rail 6.

In operation, the door 23 covering the entrance way 22 ofthe elevator 21 is displaced to its open position by It will be understood that, if stoppage at intermediate positions is not required, the driving elements 7, 27 and the driven elements 6, 26 may be suitably toothed or corrugated to replace their frictional engagement by a positive coupling. Other modifications, e.g. in the shape of the driven element (byvmaking it, for example, more curved than angular), will be readily apparent to persons skilled in the "art and may be made without departing from the spirit and scope of the invention except as limited in the appended claims.

I claim:

1. In a structure having a 'frame and a door slidable with respect to said frame, in combination, rail means extending horizontally atop said door, a shaft on said frame extending transversely above said rail means, a driving element carried by and having a surface of rotation centered on said shaft, said surface including a plurality of axially spaced portions of different diameters, said rail means being longitudinally divided into a plurali-ty of sections of different height positioned for tangential contact with respective ones of said portions in successive relative positions between said door and said 7, frame, motor means for rotating said driving element ,on

said shaft, and adjustable mounting means for said shaft on said frame, said mounting meanscomprising a pivot for said shaft having an axis offset from and parallel to said shaft, and locking means for securing said shaft in one of a plurality of angular positions about said axis;

' driving element is in the form of a stepped cylinderwith the engagement of rail 26 with stepped cylinder 27, driven by a motor 31 through a speed-reducing gear train 28, 29 lodged in;swingable housing 30. The first disk 27a, through which .a large torque is applied because of its small diameter, engages the outermost rail section 26a and produces sufficient force to overcome the inertia of the door 23. As the door begins to move, the intermediate disk 27b contacts rail section 26b to reduce the force applied and to increase the velocity of the door. Upon the engagement of rail section 260 by disk 270, the door moves at a constant rate until the cylinder disks cont-act rail sections 26b and'26a to'reduce the speed of the door preparatorily to stopping it. The door 23.

is, of course, closed in an identicalm-anner.

at least three steps and said sections are parallel to each other and are aligned with respective steps of said cylinder.

3. The combination according to claim 1 wherein said driving element is of conical configuration and said sections are contiiguously connected.

References Cited in the file of this patent UNITED STATES PATENTS 676,833 Bitner June 1 8, 1901' 772,917 Bi tuer Oct. 24, 1904 2,298,675 Cal-lender Oct. .13, 1942 2,572,196 Raque Oct. 23, 1951 2,608,872 Larson Sept. 2, 1952 2,632,258 Erickson Mar. 24, 1953 2,826,925 Singer Mar. 1, 1958 

